[libcamera-devel] [PATCH v2 2/5] ipa: proxy_worker: Reset ControlSerializer on worker

[Jacopo Mondi]

When running the IPA in isolated mode, each side of the IPC boundary
has an instance of the ControlSerializer class which is used to
serializer/deserialize controls before transmitting them on the wire.

The IPAProxyWorker, which creates and manages the process the IPA runs in,
does not reset its ControlSerializer upon an IPA::configure() call, while
the IPAProxy does, effectively creating a misalignment between the
two sides of the fence.

This obviously creates issues as one side of the IPC runs with a
populated and possibly stale cache of ControlInfoMap references, while the
other side gets reset every time a new configuration is applied to the
Camera.

Fix that by resetting the IPAProxyWorker ControlSerializer on an
IPA configure() call.

This change fixes an issue which is easily triggered by running two
consecutive capture sessions with the IPA running in isolated mode:
ERROR Serializer control_serializer.cpp:520 Can't deserialize ControlList: unknown ControlInfoMap

Fixes: 7832e19a599e ("utils: ipc: add templates for code generation for IPC mechanism")
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 .../libcamera_templates/module_ipa_proxy_worker.cpp.tmpl      | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/utils/ipc/generators/libcamera_templates/module_ipa_proxy_worker.cpp.tmpl b/utils/ipc/generators/libcamera_templates/module_ipa_proxy_worker.cpp.tmpl
index c54ecdb90a1a..c5e51532db53 100644
--- a/utils/ipc/generators/libcamera_templates/module_ipa_proxy_worker.cpp.tmpl
+++ b/utils/ipc/generators/libcamera_templates/module_ipa_proxy_worker.cpp.tmpl
@@ -79,6 +79,10 @@ public:
 
 {% for method in interface_main.methods %}
 		case {{cmd_enum_name}}::{{method.mojom_name|cap}}: {
+
+{%- if method.mojom_name == "configure" %}
+			controlSerializer_.reset();
+{%- endif %}
 		{{proxy_funcs.deserialize_call(method|method_param_inputs, '_ipcMessage.data()', '_ipcMessage.fds()', false, true)|indent(8, true)}}
 {% for param in method|method_param_outputs %}
 			{{param|name}} {{param.mojom_name}};
-- 
2.32.0